HPLC荧光法快速检测食品中的NaNO2

建立了HPLC荧光检测法测定不同食品中的NaNO2。碱性条件下以乙酸锌作为蛋白质沉淀剂纯化提取NaNO2。以C8柱作为分析柱,反相C18柱作为预柱,流动相V(水)∶V(乙腈)=60∶40,荧光检测器在激发波长375 nm发射波长415 nm条件下检测,相关系数r=0.9999,方法检出限为0.01 mg/kg,回收率84.6%~103%,相对标准偏差1.0%~5.0%。方法可用于食品中NaNO2的检测。     

高效液相色谱荧光法测定全棉织物中微量苯胺和二苯胺

建立了全棉织物中苯胺、二苯胺的高效液相色谱荧光分析方法。全棉织物采用乙腈/甲苯(3/1,V/V)为提取剂,以Carb/PSA固相萃取小柱进行净化,在Kromasil C18柱(250 mm×4.6 mm i.d.,5μm)上以水/乙腈(25/75,V/V)为流动相进行分离,采用荧光法进行检测,荧光检测波长λex为280 nm,λem为340 nm。结果表明,苯胺、二苯胺的低、中、高3个加标水平下的平均回收率分别为97.3%~103.5%和98.0%~103.4%,相对标准偏差分别为1.4%~4.2%和0.98%~4.7%,方法的检出限分别为0.3μg/kg和0.2μg/kg,定量限分别为1.0μg/kg和0.5μg/kg。采用该方法对购自市场的30份全棉织物进行检测,其中1份检出苯胺,2份同时检出苯胺和二苯胺。     

高效液相色谱法测定化妆品中防腐剂的研究

采用高效液相色谱法测定化妆品中山梨酸、苯甲酸、对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯、对羟基苯甲酸丁酯等6 种防腐剂,用Zorbax ODS柱(150×4.6 mm i.d.,5μm),磷酸二氢钾∶乙腈=90∶10(V/V)为流动相,加入磷酸调pH值为2.0,检测波长254 nm。样品用乙醇水冰乙酸(70∶29.5∶0.5,V/V)提取,回收率为90.8%~105.7%,相对标准偏差为3.1%~8.5%。     

离子交换色谱-荧光检测法测定化妆品中苯海拉明及串联质谱确证

建立了化妆品中苯海拉明的离子交换色谱-荧光检测方法及液相色谱-串联质谱确证方法。样品用含0.2%甲酸的乙腈提取,定量检测时以乙腈-0.05 mol/L KH2PO4溶液(7+3,V/V)为流动相,强阳离子交换色谱柱(250×4.6 mm,5μm)分离,荧光检测激发波长258 nm,发射波长288 nm,外标法定量,苯海拉明检出限为1.5 mg/kg,在0.2~20 mg/L范围内线性关系良好,相关系数为0.9999,方法的回收率在87.6%~106.3%范围内,相对标准偏差低于6.3%。质谱确证时用BEH C18色谱柱分离,乙腈-0.2%甲酸系统梯度洗脱,采用质谱碎片和相对离子丰度进行定性确认。     

柱前衍生高效液相色谱法测定注射液中白消安的研究

建立了一种以二乙基二硫代氨基甲酸钠(DEDC)为柱前衍生化试剂测定白消安的反相高效液相色谱分析方法。采用C18色谱柱(250 mm×4.6 mm,5μm),以V(乙腈)∶V(水)∶V(四氢呋喃)=55∶25∶20为流动相,流速为1.0mL/min,检测波长为278 nm。白消安在119.0~892.5μg/mL范围内呈良好的线性关系,r=0.9988,回收率99.81%~99.89%。     

纳米纤维固相萃取-高效液相色谱-荧光检测麻辣烫汤液中喹诺酮类药物

建立了固相萃取-高效液相色谱-荧光检测麻辣烫汤液中5种喹诺酮类抗生素的分析方法。麻辣烫汤液样品经EDTA-Mcllvaine缓冲溶液(pH 4)提取后,以HCX固相萃取小柱净化富集,用水淋洗,2%氨化甲醇洗脱。采用高效液相色谱-荧光检测器(HPLC-FLD),于激发波长280 nm,发射波长450 nm处进行检测,流动相为甲醇-水-磷酸(25∶75∶0.1,V/V,三乙胺调至pH 2.8)。麻辣烫汤液样品中氟罗沙星、诺氟沙星、沙拉沙星、环丙沙星、奥比沙星5种喹诺酮类抗生素加标回收率为72.1%~110.3%;日内相对标准偏差(RSD)为1.6%~4.3%,日间相对标准偏差为2.0%~4.3%;检出限(LOD)为1.2~5.4μg/L;定量限(LOQ)为3.9~18μg/L。本方法能够满足实际麻辣烫汤液样品的分析要求。     

UPLC法测定浓缩苹果汁中阿维菌素残留量

建立了超高效液相色谱法(UPLC)测定浓缩苹果汁阿维菌素残留的方法。样品经C18固相萃取柱(250×4.6μmi.d.,5 mm)净化分离,以V(乙腈)∶V(水)=80∶20为流动相,245 nm波长检测,流速0.3 mL/min。结果表明:本法测定的阿维菌素在4 min内可以完全分离,线性范围为0.01~200 mg/L,R2=0.9997,当添加量为0.05、0.5、1.0 mg/kg时,回收率为99.5%~108.1%,RSD为0.30%~1.1%,测定下限为0.005 mg/kg。方法可用于浓缩苹果阿维菌素残留量测定。     

反相高效液相色谱法测定人尿中利凡诺

建立了运用反相高效液相色谱法测定人尿中利凡诺的方法.采用Spherisorb C18色谱柱(250 mm×4.6 mm i.d.,5 μm);流动相: V(甲醇)∶V(乙腈)∶V(0.2 mol/L NH4Ac)=60∶37∶3;流速: 1.0 mL/min;柱温: 40 ℃;荧光检测器: 激发波长360 nm,发射波长500 nm.在5 ng/mL～1 μg/mL质量浓度范围内,呈现良好线性(r=0.9999),检出限为1 ng/mL.     

反相高效液相色谱法测定杨树中噻虫嗪的残留量

建立了一种高效液相色谱法测定杨树中噻虫嗪(Thiamethoxa) 含量的方法.采用C18柱 (250×4.6 mm),流动相为V(甲醇)∶V(乙腈)∶V(水)＝10∶10∶80 (pH≈3),流速0.8 mL/min,UV检测波长为270 nm,检测限为0.01 mg/L,线性方程为Y=2.15e+006X+1.35e+006,相关系数r=0.9991,方法回收率为91.6%,标准偏差为0.38% (n=6).     

高效液相色谱光化学在线衍生技术在11种磺胺药物残留检测中的应用

建立了磺胺药物残留的高效液相色谱-光化学在线衍生-荧光检测方法,并应用于猪肉的检测。样品经过乙腈提取,色谱柱分离后,通过在线光化学衍生后,用荧光检测器进行直接检测。优化后的色谱条件:Eclipse Plus C18柱(250 mm×4.6 mm,5.0μm),流动相为均含0.2%甲酸的乙腈、甲醇和水梯度洗脱,检测激发波长为248 nm,发射波长为350和412 nm。各种磺胺在各自浓度范围内线性相关系数R2>0.999,回收率在85.7%~101.1%之间,RSD为1.9%~6.6%(n=6),各磺胺的检出限(S/N=3)为0.2~3.0μg/kg,定量限(S/N=10)为0.5~10.0μg/kg。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.